The Kitayama whetstone has a grit rating of 8,000 but some stores claim that it is 12,000. The reason for this confusion is that the stone "seems" like a higher grit. We use the actual rating on the stone. Kitayama stones contain Magnesium salts that will dissolve in water so it is recommended that you do not leave the stone in water for long periods of time. Just splash water on it and start sharpening.
We recently switched these stones to the baseless version after our customers voted 10 to 1 in favor of the baseless version. The baseless stone allows you to sharpen on both sides.